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Finding the Fourth Proportional to 78.29, 117.26 and 66.79

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Solution

The fourth proportional to 78.29, 117.26 and 66.79 is: 100.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.29 : 117.26 = 66.79 : x
  2. Step 2: Convert to fraction form
    78.29/117.26 = 66.79/x
  3. Step 3: Cross multiply
    78.29x = 117.26 × 66.79
  4. Step 4: Simplify right side
    78.29x = 7,831.80
  5. Step 5: Solve for x
    x = 7,831.80/78.29
  6. Step 6: Final answer
    x = 100.04

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.